1. Field of the Invention
The present invention relates generally to computer synchronization systems and, more particularly, to time synchronization systems for interacting computers. Specifically, the present invention relates to an improved time synchronization system for enhancing the speed and flow of data transmission between interacting computers over a network and the Internet.
2. Description of the Prior Art
All computers function by toggling bits on and off according to the pulse of a master clock that cycles the CPU through steps of a program. The CPU controls all of the various functions of the computer. The faster the master clock, the faster the computer is able to perform calculations. Synchronization within the computer allows bits to be organized into bytes, which are strings of binary numbers that represent commands or data, and the bytes can be transferred to different areas of the computer to perform different functions. Modern computers measure clock speed in MHz, or millions of cycles per second.
Bytes are transferred between computers using data transfer mechanisms such as modems or other types of network protocols. Speeds of typical modem access, which most people use to interface with a network or the global Internet, are measured in KBS or thousands of bytes per second. There are many applications in which it is either necessary or desirable to distribute the acquisition or processing of data over a number of computer-controlled stations or processors. In order to maintain time synchronization between the data and control streams of the computers or processors, current systems generally depend on shared hardware for their synchronization or wireless transmission of time information from a common clock to each of the stations. In such cases, uncertainty due to communications delay determines the overall error in time resolution of the system.
In a system having multiple computers or stations, it is desirable for each station or computer to have its own clock so that the computer's CPU can continue operating even if synchronization with a common clock is temporarily lost. However, such clocks may operate at slightly different frequencies, further compounding the time resolution/synchronization problem.
Numerous arrangements have been proposed to address the computer time synchronization problem. Master/slave clock arrangements have been proposed including those using satellites such as illustrated in the U.S. Pat. No. 4,882,739. In addition, time synchronization apparatus and methods using the global positioning satellite (GPS) system have also been proposed as in U.S. Pat. Nos. 5,757,786 and 5,440,313, and in the AT&T Primary Reference Clock (PRC) system. Also, the Network Time Protocol (NTP) is used in the Internet to synchronize individual computers to national standard time by providing a time stamp from primary time servers and provides accuracy's generally in the range of a millisecond or two in Local-Area Networks (LANs) and up to a few tens of milliseconds in global Wide-Area Networks (WANs). However, while global positioning satellite receivers have a timing resolution accurate to 1 Ns, or one billionth of a second, the timing synchronization between computers has still not been adequately coordinated and controlled.
In addition, massively parallel supercomputers requiring high-speed computer interaction have been and are continuing to be developed. Beowulf parallel workstations include numerous computers at one location, called pile of PCs, tied together in a high-speed LAN system thereby achieving supercomputing performance. Avalon, being developed at the Los Alamos National Laboratory, is another supercomputing pile of PCs consisting of about 70 desktop computers linked together in a LAN. Jini technology, being developed by Sun Microsystems, represents a dynamic distributed system wherein software development provides the ability to establish communication, sharing and exchange of services between any hardware or software on a network. "Param-10,000" is a new supercomputer being developed by India's Center for Development of Advanced Computing and is to be the main node for a new supercomputer WAN called Paramnet which will be accessible through the global Internet. Finally, Microsoft is developing a software based self-tuning operating system for running applications across PCs, termed "Millennium". As a result of the above, it is clear that there remains an increasing need for a timing synchronization scheme which has exceptionally high resolution adequate to provide even the fastest computers with a highly accurate timing reference that can be utilized all the way from the processor level to the global Internet level.